97 lines
3.3 KiB
C
97 lines
3.3 KiB
C
/*-
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* Copyright (c) 2012-2013 Universitetet i Oslo
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id$
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*/
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#ifndef OATH_H_INCLUDED
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#define OATH_H_INCLUDED
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/*
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* Maximum time step for TOTP: 10 minutes, which RFC 6238 cites as an
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* example of an unreasonably large time step.
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*/
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#define OATH_MAX_TIMESTEP 600
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/*
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* Maximum key length in bytes. HMAC has a 64-byte block size; if the key
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* K is longer than that, HMAC derives a new key K' = H(K).
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*/
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#define OATH_MAX_KEYLEN 64
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/* estimate of output length for base32 encoding / decoding */
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#define base32_enclen(l) (size_t)(((l + 4) / 5) * 8)
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#define base32_declen(l) (size_t)(((l + 7) / 8) * 5)
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/* base32 encoding / decoding */
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int base32_enc(const uint8_t *, size_t, char *, size_t *);
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int base32_dec(const char *, size_t, uint8_t *, size_t *);
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/* estimate of output length for base64 encoding / decoding */
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#define base64_enclen(l) (size_t)(((l + 2) / 3) * 4)
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#define base64_declen(l) (size_t)(((l + 3) / 4) * 3)
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/* base64 encoding / decoding */
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int base64_enc(const uint8_t *, size_t, char *, size_t *);
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int base64_dec(const char *, size_t, uint8_t *, size_t *);
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/* mode: hotp (event mode) or totp (time-synch mode) */
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enum oath_mode { om_undef, om_hotp, om_totp };
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/* hash function */
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enum oath_hash { oh_undef, oh_sha1, oh_sha256, oh_sha512, oh_md5 };
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/* key structure */
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struct oath_key {
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/* mode and parameters */
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enum oath_mode mode;
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unsigned int digits;
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uint64_t counter;
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unsigned int timestep; /* in seconds */
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/* hash algorithm */
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enum oath_hash hash;
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/* label */
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size_t labellen; /* bytes incl. NUL */
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char *label;
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/* key */
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size_t keylen; /* bytes */
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uint8_t *key;
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/* buffer for label + NUL + key */
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size_t datalen; /* bytes */
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uint8_t data[];
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};
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unsigned int oath_hotp(const uint8_t *, size_t, uint64_t, unsigned int);
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unsigned int oath_totp(const uint8_t *, size_t, unsigned int);
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#endif
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